The need for a portable heat transfer mechanism manifests itself in numerous circumstances. Cool fluids are required by outside workers in desert environments and hot summer weather, conversely warm fluids are required by the same persons in cold environments and cold/freezing winter weather. Other applications include the need of home brewers to maintain a specific temperature range for their fermenting beer, home vintners for their fermenting wine. Most portable mechanical heating and cooling devices have inherent disadvantages. Heating devices usually operate at elevated temperatures and many require flammable fuel. Both can be extremely hazardous. Cooling mechanisms are bulky, heavy, mechanically complex and frequently employ materials designated as ozone depleting substances or otherwise environmentally adverse.
Thermoelectric modules (Peltier elements) based upon the Peltier effect, for heating and cooling, are well known in the art. Research and technical advances have been dramatically lowering the cost and broadening the applications for these devices. Small, portable food warmer/chillers powered from vehicle electrical systems, small air coolers, and cooling modules for electronic circuitry have been expanding areas of thermoelectric module application.